When a truck, trailer or some other vehicle is parked at a loading dock, often a vehicle restraint is used to keep the truck from inadvertently moving away from an elevated platform of the dock. Preventing the vehicle from inadvertently moving forward allows a forklift truck to safely drive between the dock platform and the truck for the purpose of loading or unloading the cargo inside the truck.
A variety of vehicle restraints are available that can be installed at a loading dock. For example, a vehicle restraint can include an ICC-style restraint that engages a truck's RIG (Rear Impact Guard), also known as an ICC bar. An ICC bar is a beam that extends horizontally across the rear of a truck, just below the truck bed. Its primary purpose is to prevent an automobile from under-riding the truck in a rear-end collision. However, not all trucks have an ICC bar that can be readily engaged by an ICC-style restraint. Moreover, ICC bars are not prevalent outside the United States, so in those cases a wheel restraint can be used for blocking one or more of the truck's wheels. Perhaps the most common wheel restraint is simply a wheel chock that wedges between the driveway and the underside of the wheel. However, wheel chocks often slip out of position on driveways that are slippery due to oil, rain, ice, sand, gravel or dirt. Moreover, wheel chocks usually are loose items that do not permanently attach to the loading dock area, so they often get misplaced.